Single-layer multipass Fe-0.3C-15Cr-1Ni alloy cladding layers were prepared on the surface of 3Cr13 martensitic stainless steel using different laser powers. The effects of laser power on the size of dendrite morphology, carbide size and distribution, and wear and corrosion resistance of Fe-0.3C-15Cr-1Ni alloy cladding were investigated. With the increase of laser power, the number of carbides gradually decreases, and the microhardness, wear resistance, and corrosion resistance of the cladding layer show a pattern of increasing and then decreasing. When the laser power is 1400 W, the hardness, wear resistance, and corrosion resistance of the cladding layer are the best, and the stability of the coefficient of friction is the best. It has the largest pitting potential, the widest width of the passivation zone, the lowest reactivation rate, a significant increase in matrix impedance, smaller pits after immersion corrosion, and the best corrosion resistance. This is due to 1400-W microstructure uniformity being better, the alloying elements in the matrix, and carbide reasonable distribution, thus improving the matrix wear and corrosion resistance.